One of methods of detecting a nucleic acid is a method with use of a probe whose fluorescence emission is controllable by “exciton effect (exciton coupling effect)”, as to whether or not to emit fluorescence.
As one example of a probe for detecting a nucleic acid by using the exciton effect as described above, Patent Literature 1 discloses a probe which contains a compound having a structure derived from mononucleoside or mononucleotide. The compound is, for example, attached to two fluorescent molecules. The probe emits extremely weak fluorescence while not being bound to DNA etc. because a structure of the probe is distorted and an exciton coupling causes quenching. The probe, however, emits strong fluorescence when the probe is hybridized with DNA or RNA because such distortion of the structure is solved and the structure is fixed.